射频消融对兔心内膜单相动作电位影响的实验研究

Effect of radiofrequency ablation on endocardial monophasic action potentials of rabbit

目的探讨射频导管消融（ＲＦＣＡ）对心内膜单相动作电位（ＭＡＰ）的影响，为进一步完善ＲＦＣＡ的过程提供理论依据。方法选取健康家兔３６只，用接触电极导管监测ＲＦＣＡ前后兔心内膜的ＭＡＰ变化并观察ＲＦＣＡ不同时间（１０～６０秒）和不同温度（４０～９０℃）水平ＭＡＰ的变化。结果（１）单相动作电位振幅（ＭＡＰＡ）和０相最大上升速度（Ｖｍａｘ）随ＲＦＣＡ时间延长及温度升高而降低或下降，持续放电３０秒或温度达５０℃以后ＭＡＰＡ及Ｖｍａｘ几乎不再变化；（２）整个过程的单相动作电位时程（ＭＡＰＤ）无明显变化且未见心律失常发生。结论（１）当ＲＦＣＡ温度达５０℃心肌电活动以及心肌组织已经产生有效的损伤；ＲＦＣＡ对ＭＡＰＤ不产生影响，故不易导致心律失常（２）将ＭＡＰ记录与温度监测结合起来。

Objective To study the effect of radiofrequency ablation (RFCA) on endocardial monophasic action potentials (MAP). Methods The contact electrode catheter was used to monitor the changes in endocardial MAP before and after RFCA on 36 healthy rabbits and observe the changes in MAP in different time points (1060 seconds) and different temperatures (4090℃) of RFCA. Results (1)Both the MAP amplitude and maximum upstroke velocity of phase 0 (Vmax) were decreased with the prolongation of time and increase in temperature. MAP amplitude and Vmax almost did not change after the duration of RFCA delivery was over 30 seconds or the temperature was up to 50℃; (2) the duration of MAP did not change and no arhythmia occurred in whole RFCA procession. Conclusion (1) The change in myocardial electric activity and tissue lesion were obvious when RFCA temperature was up to 50℃; RFCA had no effect on the duration of MAP. Therefore, it was not likely to result in arrhythmia; (2) to combine MAP recording and temperature monitoring was useful in the evaluation of the contacting status between catheter and myocardial tissue before RFCA and myocardial lesion after RFCA.